Ohio State researcher hopes to turn vibrations, movement into energy

Thursday

Mar 3, 2016 at 12:01 AMMar 6, 2016 at 10:26 AM

You know when you reach the top of a skyscraper and feel it swaying in the wind? Or those vibrations you feel as you drive over a suspension bridge? Those movements hold energy that Ryan Harne, an assistant professor in mechanical and aerospace engineering at Ohio State University, hopes to one day harness.

Laura Arenschield, The Columbus Dispatch

You know when you reach the top of a skyscraper and feel it swaying in the wind? Or those vibrations you feel as you drive over a suspension bridge?

Those movements hold energy that Ryan Harne, an assistant professor in mechanical and aerospace engineering at Ohio State University, hopes to one day harness.

The goal is to convert that energy into clean power. The small vibrations don't produce enough energy to power a house, but they could power sensors on pipelines, bird-tracking devices or something the size of a pacemaker.

While those things require little energy, replacing batteries or running electrical lines to them can be risky, costly or impractical. "You're talking microwatts in some cases," Harne said.

It's not exactly a new technology. Researchers have been studying how to capture that kind of energy for decades, using it in some cases to power sensors on bridges and piers. In those cases, the very things that can damage the structure also can power our ability to sense it.

"You have this broad-band spectrum (of movements and vibrations)," Harne said. "The question is, how do you develop a device that is very sensitive (to capture that energy)?"

Scientists at Virginia Tech, Massachusetts Institute of Technology and other universities have long studied capturing this kind of energy. At Virginia Tech, they've figured out how to harness energy from ocean waves and railroad tracks. At MIT, they have studied how best to capture energy created from small vibrations similar in scale to what Harne is studying.

When Harne was a post-doctoral researcher at the University of Michigan, he and his colleagues studied how tree movements created energy. When breezes hit, trees sway slightly at their trunks and even more in big branches. As branches get smaller toward the treetops, they vibrate even more in the wind.

Harne thought there had to be a way to recreate that phenomenon and capture energy created by small vibrations. "The intent is to look at nature and, you could say, be inspired by its structure. But I would say learn from it," he said.

In a paper published Feb. 17 in the Journal of Sound and Vibrations, Harne describes the prototype he and his colleagues built in Michigan. It's a treelike structure complete with a trunk and branches. When something forces it to move, a piece along the branches captures that energy.

Harne came to Ohio State about eight months ago and brought the prototype with him. Now director of the OSU Laboratory of Sound & Vibration Research, Harne said he is continuing to work on the technology in hopes of building it into something with practical applications. His lab has a proposal for funding.

He and others acknowledge that there will be challenges to putting the technology into practice.

Lei Zuo, a professor at Virginia Tech said although he has found various ways to harness that energy, turning it into electricity on a scale large enough to be useful is difficult. "It's tricky," Zuo said.

He said Harne's research "should be encouraged," and that the key eventually will be getting the technology to a place where it is useful worldwide.

Harne knows that and said the technology will need to turn energy from vibrations into something that outperforms batteries or electrical line transmissions.

To do that, he will have to develop new tools to predict how energy captured from vibrations performs. But he's optimistic.

"We have things that don't add up," Harne said. "We need greater understanding as to how to put these biologically inspired mechanisms to work."

larenschield@dispatch.com

@larenschield

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